The field of the present invention relates to the delivery of energy impulses (and/or fields) to bodily tissues for therapeutic purposes. The invention relates more specifically to devices and methods for treating conditions associated with autism and other disorders of psychological development. The energy impulses (and/or fields) that are used to treat those conditions comprise electrical and/or electromagnetic energy, delivered non-invasively to the patient.
The use of electrical stimulation for treatment of medical conditions is well known. For example, electrical stimulation of the brain with implanted electrodes (deep brain stimulation) has been approved for use in the treatment of various conditions, including pain and movement disorders such as essential tremor and Parkinson's disease [Joel S. PERLMUTTER and Jonathan W. Mink. Deep brain stimulation. Annu. Rev. Neurosci 29 (2006):229-257].
Another application of electrical stimulation of nerves is the treatment of radiating pain in the lower extremities by stimulating the sacral nerve roots at the bottom of the spinal cord [Paul F. WHITE, Shitong Li and Jen W. Chiu. Electroanalgesia: Its Role in Acute and Chronic Pain Management. Anesth Analg 92 (2001):505-513; U.S. Pat. No. 6,871,099, entitled Fully implantable microstimulator for spinal cord stimulation as a therapy for chronic pain, to WHITEHURST, et al].
The form of electrical stimulation that is most relevant to the present invention is vagus nerve stimulation (VNS, also known as vagal nerve stimulation). It was developed initially for the treatment of partial onset epilepsy and was subsequently developed for the treatment of depression and other disorders. The left vagus nerve is ordinarily stimulated at a location within the neck by first surgically implanting an electrode there and then connecting the electrode to an electrical stimulator [U.S. Pat. No. 4,702,254 entitled Neurocybernetic prosthesis, to ZABARA; U.S. Pat. No. 6,341,236 entitled Vagal nerve stimulation techniques for treatment of epileptic seizures, to OSORIO et al; U.S. Pat. No. 5,299,569 entitled Treatment of neuropsychiatric disorders by nerve stimulation, to WERNICKE et al; G. C. ALBERT, C. M. Cook, F. S. Prato, A. W. Thomas. Deep brain stimulation, vagal nerve stimulation and transcranial stimulation: An overview of stimulation parameters and neurotransmitter release. Neuroscience and Biobehavioral Reviews 33 (2009):1042-1060; GROVES D A, Brown V J. Vagal nerve stimulation: a review of its applications and potential mechanisms that mediate its clinical effects. Neurosci Biobehav Rev 29 (2005):493-500; Reese TERRY, Jr. Vagus nerve stimulation: a proven therapy for treatment of epilepsy strives to improve efficacy and expand applications. Conf Proc IEEE Eng Med Biol Soc. 2009; 2009:4631-4634; Timothy B. MAPSTONE. Vagus nerve stimulation: current concepts. Neurosurg Focus 25 (3, 2008):E9, pp. 1-4; ANDREWS, R. J. Neuromodulation. I. Techniques-deep brain stimulation, vagus nerve stimulation, and transcranial magnetic stimulation. Ann. N.Y. Acad. Sci. 993 (2003):1-13; LABINER, D. M., Ahern, G. L. Vagus nerve stimulation therapy in depression and epilepsy: therapeutic parameter settings. Acta. Neurol. Scand. 115 (2007):23-33].
Many such therapeutic applications of electrical stimulation involve the surgical implantation of electrodes within a patient. In contrast, devices used for the procedures that are disclosed here do not involve surgery. Instead, the present devices and methods stimulate nerves by transmitting energy to nerves and tissue non-invasively. A medical procedure is defined as being non-invasive when no break in the skin (or other surface of the body, such as a wound bed) is created through use of the method, and when there is no contact with an internal body cavity beyond a body orifice (e.g, beyond the mouth or beyond the external auditory meatus of the ear). Such non-invasive procedures are distinguished from invasive procedures (including minimally invasive procedures) in that the invasive procedures insert a substance or device into or through the skin (or other surface of the body, such as a wound bed) or into an internal body cavity beyond a body orifice.
For example, transcutaneous electrical stimulation of a nerve is non-invasive because it involves attaching electrodes to the skin, or otherwise stimulating at or beyond the surface of the skin or using a form-fitting conductive garment, without breaking the skin [Thierry KELLER and Andreas Kuhn. Electrodes for transcutaneous (surface) electrical stimulation. Journal of Automatic Control, University of Belgrade 18(2, 2008):35-45; Mark R. PRAUSNITZ. The effects of electric current applied to skin: A review for transdermal drug delivery. Advanced Drug Delivery Reviews 18 (1996) 395-425]. In contrast, percutaneous electrical stimulation of a nerve is minimally invasive because it involves the introduction of an electrode under the skin, via needle-puncture of the skin.
Another form of non-invasive electrical stimulation is magnetic stimulation. It involves the induction, by a time-varying magnetic field, of electrical fields and current within tissue, in accordance with Faraday's law of induction. Magnetic stimulation is non-invasive because the magnetic field is produced by passing a time-varying current through a coil positioned outside the body. An electric field is induced at a distance, causing electric current to flow within electrically conducting bodily tissue. The electrical circuits for magnetic stimulators are generally complex and expensive and use a high current impulse generator that may produce discharge currents of 5,000 amps or more, which is passed through the stimulator coil to produce a magnetic pulse. The principles of electrical nerve stimulation using a magnetic stimulator, along with descriptions of medical applications of magnetic stimulation, are reviewed in: Chris HOVEY and Reza Jalinous, The Guide to Magnetic Stimulation, The Magstim Company Ltd, Spring Gardens, Whitland, Carmarthenshire, SA34 0HR, United Kingdom, 2006. In contrast, the magnetic stimulators that are disclosed here are relatively simpler devices that use considerably smaller currents within the stimulator coils. Accordingly, they are intended to satisfy the need for simple-to-use and less expensive non-invasive magnetic stimulation devices, for use in treating autism and other developmental conditions, as well as use in treating other conditions.
Potential advantages of such non-invasive medical methods and devices relative to comparable invasive procedures are as follows. The patient may be more psychologically prepared to experience a procedure that is non-invasive and may therefore be more cooperative, resulting in a better outcome. Non-invasive procedures may avoid damage of biological tissues, such as that due to bleeding, infection, skin or internal organ injury, blood vessel injury, and vein or lung blood clotting. Non-invasive procedures are generally painless and may be performed without the dangers and costs of surgery. They are ordinarily performed even without the need for local anesthesia. Less training may be required for use of non-invasive procedures by medical professionals. In view of the reduced risk ordinarily associated with non-invasive procedures, some such procedures may be suitable for use by the patient or family members at home or by first-responders at home or at a workplace. Furthermore, the cost of non-invasive procedures may be significantly reduced relative to comparable invasive procedures.
In the present invention, noninvasive electrical and/or magnetic stimulation of a vagus nerve is used to treat or manage pervasive developmental disorders, such as autism, which are neuro-developmental disorders characterized by problems involving a child's socialization, communication, and repetitive or other unusual behavior. Such disorders are listed in entry F84 in the International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10). They include childhood autism (F84.0), atypical autism (F84.1), Rett syndrome (F84.2), other childhood disintegrative disorder (F84.3), overactive disorder associated with mental retardation and stereotyped movements (F84.4), Asperger syndrome (F84.5), other pervasive developmental disorders (F84.8), and unspecified pervasive developmental disorder (F84.9) [World Health Organization. International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10) Geneva, Switzerland: The WHO (English edition: 10th revision, 2008), entry F84].
A similar classification of pervasive developmental disorders appears in The Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV)—Autistic Disorder (299.00), Pervasive Developmental Disorder, Not Otherwise Specified (299.80), Asperger's Disorder (299.80), Rett's Disorder (299.80), and Childhood Disintegrative Disorder (299.10) [American Psychiatric Association. Criteria for Autism in: Diagnostic and Statistical Manual of Mental disorders (4th ed., text rev.; DSM-IV). Washington, D.C.: The Association (2000), code 299]. However, the 5th edition of The Diagnostic and Statistical Manual of Mental Disorders (DSM-V), which will be forthcoming in 2013, will combine several of these disorders (including Asperger syndrome and Pervasive Developmental Disorder Not Otherwise Specified—abbreviated as PDD-NOS) into a single entity, namely, autism spectrum disorders (ASD).
According to the proposed DSM-V revised criteria for autism spectrum disorders, an autistic spectrum individual must meet the following A, B, C and D criteria. (A). Persistent deficits in social communication and social interaction across contexts, not accounted by general developmental delays and manifest by all three of the following: (1) Deficits in social-emotional reciprocity . . . ; (2) Deficits in nonverbal communicative behaviors used for social interaction . . . ; (3) Deficits in developing and maintaining relationships appropriate to developmental level, beyond those with caregivers. (B). Restricted, repetitive patterns of behavior, interests or activities as manifested by at least two of the following. (1) Stereotyped or repetitive speech, motor movements, or use of objects . . . ; (2) Excessive adherence to routines, ritualized patterns of verbal or nonverbal behavior, or excessive resistance to change . . . ; (3) Highly restricted, fixated interests that are abnormal in intensity or focus . . . ; (4) Hyper- or hypo-reactivity to sensory input or unusual interests in sensory aspects of environment . . . ; (C). Symptoms must be present in early childhood . . . ; (D). Symptoms together limit and impair everyday functioning.
Although ASD is already in widespread use as a term, the reconceptualization of ASD in DSM-V is controversial for at least the following reason. Currently, the most common diagnosis among autistic spectrum individuals is PDD-NOS, which is sometimes referred to as atypical “mild autism”. Similarly, Asperger syndrome is sometimes referred to as a “higher functioning autism”. Some individuals who are presently diagnosed with Asperger syndrome, as well as PDD-NOS individuals without repetitive or ritualized behaviors, may not be considered autistic under the revised DSM-V criteria. This may affect the availability of services in the United States that they currently obtain (e.g., special schooling, health care, and behavioral therapies). [HAPPE, F. Criteria, categories, and continua: Autism and related disorders in DSM-5. Journal of the American Academy of Child & Adolescent Psychiatry 50 (2011): 540-542; McPARTLAND, J. C., Reichow, B., and Volkmar, F. R. Sensitivity and specificity of proposed DSM-5 diagnostic criteria for autism spectrum disorder. Journal of the American Academy of Child & Adolescent Psychiatry 51 (2012):368-383; WORLEY, A. and Matson, J. L. Comparing symptoms of autism spectrum disorders using the current DSM-IV-TR diagnostic criteria and the proposed DSM-V diagnostic criteria. Research in Autism Spectrum Disorders 6 (2012):965-970; FRAZIER, T. W., Youngstrom, E. A., Speer, L., Embacher, R., Law, P., Constantino, J . . . . Eng, C. Validation of proposed DSM-5 criteria for autism spectrum disorder. Journal of the American Academy of Child and Adolescent Psychiatry 51 (2012):28-40].
The diagnosis of a particular pervasive developmental disorder, such as autism, is made after extended observation and interaction with a child. Best practices include an initial routine developmental surveillance of the child, in which a professional looks for certain age-specific developmental milestones. If the surveillance reveals clinical clues of possible autism, it is followed by the diagnosis and evaluation. A screening test for autism in young children, often the Checklist for Autism in Toddlers (CHAT), is then conducted. If the CHAT screening suggests possible autism, further assessment is performed. The diagnosis of autism (or other developmental disorder) often does not occur until the child reaches the age of 3 or 4 [Pauline A. FILIPEK, Pasquale J. Accardo, Grace T. Baranek, et al. The screening and diagnosis of autistic spectrum disorders. J Autism Dev Disord. 29(6, 1999):439-484; FILIPEK P A, Accardo P J, Ashwal S, et al. Practice parameter: screening and diagnosis of autism: report of the Quality Standards Subcommittee of the American Academy of Neurology and the Child Neurology Society. Neurology 55(4, 2000):468-479; New York State Department of Health (NYSDH). Clinical practice guideline: Quick Reference Guide for Parents and Professionals. Autism/Pervasive developmental disorders assessment and intervention for young children (age 0-3 years). Publication No. 4216, Albany, N.Y. 1999, pp. 1-97; BAIRD, T Charman, A Cox, S Baron-Cohen, J Swettenham, S Wheelwright, and A Drew. Screening and surveillance for autism and pervasive developmental disorders. Arch Dis Child 84(6, 2001): 468-475; KLIN, A., Saulnier, C. D., Tsatsanis, K. D., & Volkmar, F. R. (2005) Clinical evaluation in autism spectrum disorders: Psychological assessment within a transdisciplinary framework. In F. R. Volkmar, R. Paul, A. Klin, & D. Cohen (Eds.), Handbook of autism and pervasive developmental disorders: 3rd Edition, John Wiley & Sons, pp. 772-798; Sara Jane WEBB and Emily J. H. Jones. Early Identification of Autism—Early Characteristics, Onset of Symptoms, and Diagnostic Stability Infants & Young Children 22(2, 2009):100-118].
Several testing instruments are commonly used to assess the likelihood of autism, including The Autism Behavior Checklist (ABC), Autism Diagnostic Interview-Revised (ADI-R), The Childhood Autism Rating Scale (CARS), The Pre-Linguistic Autism Diagnostic Observation Schedule (PL-ADOS), and The Autism Diagnostic Observation Schedule and its generic version (ADOS-G) [SCHOPLER E, Reichler R J, DeVellis R F, Daly K. Toward objective classification of childhood autism: Childhood Autism Rating Scale (CARS). J Autism Dev Disord 10(1, 1980):91-103; RELLINI E, Tortolani D, Trillo S, Carbone S, Montecchi F. Childhood Autism Rating Scale (CARS) and Autism Behavior Checklist (ABC) correspondence and conflicts with DSM-IV criteria in diagnosis of autism. J Autism Dev Disord 34(6, 2004):703-708. LORD C, Rutter M, Goode S, Heemsbergen J, Jordan H, Mawhood L, Schopler E. Autism diagnostic observation schedule: a standardized observation of communicative and social behavior. J Autism Dev Disord 19(2, 1989):185-212; LORD C, Rutter M, Le Couteur A. Autism Diagnostic Interview-Revised: a revised version of a diagnostic interview for caregivers of individuals with possible pervasive developmental disorders. J Autism Dev Disord 24(5, 1994):659-685; DILAVORE P C, Lord C, Rutter M. The pre-linguistic autism diagnostic observation schedule. J Autism Dev Disord 25(4, 1995):355-379; LORD C, Risi S, Lambrecht L, Cook E H Jr, Leventhal B L, DiLavore P C, Pickles A, Rutter M. The autism diagnostic observation schedule-generic: a standard measure of social and communication deficits associated with the spectrum of autism. J Autism Dev Disord 30(3, 2000):205-223].
An individual might be diagnosed as having Asperger syndrome under the ICD-10 criteria, and autism spectrum disorder under the DSM-V criteria, or Asperger syndrome under DSM-IV criteria. In that regard, a diagnostic complication is that under the hierarchical rules of DSM-IV, a dual diagnosis of autism spectrum disorder with attention-deficit hyperactivity disorder (ADHD) is not possible, because signs for the ADHD must not be due to the course of a pervasive developmental disorder. In contrast, under ICD-10, a dual Asperger and ADHD diagnosis is possible, provided that the Asperger syndrome individual also exhibits traits of ADHD such as hyperactivity, impulsiveness, short attention span, and executive function deficits. This illustrates the diagnostic confusion that is inherent in the use of different disease classifications (ICD versus DSM), which is significant because different diagnoses may require different treatments [Michael FITZGERALD and Aiden Corvin. Diagnosis and differential diagnosis of Asperger syndrome. Advances in Psychiatric Treatment 7(2001): 310-318]. The confusion might be avoided if diagnosis could be made on the basis of laboratory tests rather than solely on the basis of behavioral criteria, but biomarkers that would be useful for that purpose are not yet available [WALSH P, Elsabbagh M, Bolton P, Singh I. In search of biomarkers for autism: scientific, social and ethical challenges. Nat Rev Neurosci 12(10, 2011):603-612; VEENSTRA-VanderWeele J, Blakely R D. Networking in autism: leveraging genetic, biomarker and model system findings in the search for new treatments. Neuropsychopharmacology 37(1, 2012):196-212; RATAJCZAK H V. Theoretical aspects of autism: biomarkers—a review. J Immunotoxicol 8(1, 2011):80-94; HENDREN R L, Bertoglio K, Ashwood P, Sharp F. Mechanistic biomarkers for autism treatment. Med Hypotheses 73(6, 2009): 950-954; SKJELDAL O H, Sponheim E, Ganes T, Jellum E, Bakke S. Childhood autism: the need for physical investigations. Brain Dev 20(4, 1998):227-233].
Before the 1990s, the prevalence of autism spectrum disorders was thought to be no more than 5 per 10,000 individuals. Many recent epidemiological studies tend to conclude that prevalence of autistic disorder falls between 10 and 20 per 10,000. Some reports find that the incidence is 60 per 10,000 or more. Boys are affected with ASDs more frequently than are girls by a ratio of 4.3:1. The incidence of all pervasive developmental disorders has been estimated to be between 30 and 116 per 10,000, with a prevalence of 2.5 per 10,000 for Asperger syndrome and 15 per 10,000 for PDD-NOS. The data do not show significant prevalence differences according to geographic region, ethnic/cultural factors, or socioeconomic factors. The increasing prevalence is most likely due to the broadening concept of autistic spectrum disorder over the years and to a greater awareness of these disorders among professionals and the public at large. The lifetime per capita incremental cost of autism has been estimated to be $3.2 million, with adult care and lost productivity being the largest components of costs [ELSABBAGH M, Divan G, Koh Y J, et al. Global prevalence of autism and other pervasive developmental disorders. Autism Res 5(3, 2012):160-179; NEWSCHAFFER C J, Croen L A, Daniels J, et al. The epidemiology of autism spectrum disorders. Annu Rev Public Health 28 (2007):235-258; RUTTER M. Incidence of autism spectrum disorders: changes over time and their meaning. Acta Paediatr 94(1, 2005):2-15; GANZ M L. The lifetime distribution of the incremental societal costs of autism. Arch Pediatr Adolesc Med 161(4, 2007):343-349].
Many environmental risk factors have been investigated as potential causes of ASD, including certain foods, infectious disease, heavy metals, solvents, diesel exhaust, PCBs, phthalates and phenols used in plastic products, pesticides, brominated flame retardants, alcohol, smoking, illicit drugs, vaccines, and prenatal stress. However, only a few such as rubella exposure have been shown to be significant causative agents [NEWSCHAFFER C J, Croen L A, Daniels J, et al. The epidemiology of autism spectrum disorders. Annu Rev Public Health 28 (2007):235-258].
Autism has a strong genetic basis, as evidenced by the study of twins and other relatives of individuals with ASD. However, the genetics of autism is complex. The number of gene mutations found to carry risk for ASD is now well into the hundreds, with no single locus accounting for more than 1% of cases. Furthermore, these mutations may be associated not only with ASD, but also with disorders such as epilepsy, mental retardation, and schizophrenia. Some such mutations are particularly associated with genetic disorders in which autism is common, such as Joubert Syndrome, Smith-Lemli-Opitz syndrome, Tuberous Sclerosis and Fragile X. Practical use of these genetic markers may have to wait until it is better understood how expression of the genes occurs at different times during the embryological development of the brain [FREITAG C M. The genetics of autistic disorders and its clinical relevance: a review of the literature. Mol Psychiatry 12(1, 2007):2-22; KUMAR R A, Christian S L. Genetics of autism spectrum disorders. Curr Neurol Neurosci Rep 9(3, 2009):188-197; GESCHWIND D H. Genetics of autism spectrum disorders. Trends Cogn Sci 15(9, 2011):409-416; STATE M W, Šestan N. Neuroscience. The emerging biology of autism spectrum disorders. Science 337(6100, 2012):1301-1303].
In addition to the above-mentioned genetic syndromes, such as Fragile X and tuberous sclerosis, autism is frequently comorbid with mood disorders, phobias, obsessive compulsive disorders, anxiety disorders, and psychosis. As noted above, it is also frequently comorbid with attention deficit hyperactivity disorder, provided that ICD-10 criteria are used [MATSON J L, Nebel-Schwalm M S. Comorbid psychopathology with autism spectrum disorder in children: an overview. Res Dev Disabil 28(4, 2007):341-352]. Intellectual disability or mental handicap (previously known as mental retardation) may occur in as many as 75% of autistic children, although special testing methods may be necessary to distinguish autism from intellectual disability [OSTERLING J A, Dawson G, Munson J A. Early recognition of 1-year-old infants with autism spectrum disorder versus mental retardation. Dev Psychopathol 14(2, 2002):239-251]. Many other medical symptoms or disorders are commonly reported in children with autism, including epilepsy, immune system dysregulation, gastrointestinal symptoms, motor impairment, sensory dysfunction, feeding difficulties/eating disorders, and sleep disorders [NEWSCHAFFER C J, Croen L A, Daniels J, et al. The epidemiology of autism spectrum disorders. Annu Rev Public Health 28 (2007):235-258; TUCHMAN R, Cuccaro M, Alessandri M. Autism and epilepsy: historical perspective. Brain Dev 32 (2010):709-718; TUCHMAN R, Rapin I. Epilepsy in autism. Lancet Neurol 1(6, 2002):352-358; BOLTON P F, Carcani-Rathwell I, Hutton J, Goode S, Howlin P, Rutter M. Epilepsy in autism: features and correlates. Br J Psychiatry 198(4, 2011):289-294; STAFSTROM C E, Hagerman P J, Pessah I N. Pathophysiology of Epilepsy in Autism Spectrum Disorders. In: Noebels J L, Avoli M, Rogawski M A, Olsen R W, Delgado-Escueta A V, editors. Jasper's Basic Mechanisms of the Epilepsies. 4th edition. Bethesda (MD): National Center for Biotechnology Information (US), 2012, pp. 1-19; PARDO C A, Vargas D L, Zimmerman A W. Immunity, neuroglia and neuroinflammation in autism. Int Rev Psychiatry 17(6, 2005):485-495; ERICKSON C A, Stigler K A, Corkins M R, Posey D J, Fitzgerald J F, McDougle C J. Gastrointestinal factors in autistic disorder: a critical review. J Autism Dev Disord 35(6, 2005):713-727; MING X, Brimacombe M, Wagner G C. Prevalence of motor impairment in autism spectrum disorders. Brain Dev 29(9, 2007):565-570; ROGERS S J, Ozonoff S. Annotation: what do we know about sensory dysfunction in autism? A critical review of the empirical evidence. J Child Psychol Psychiatry 46(12, 2005):1255-1268].
In the remainder of this background section, current methods for treating or managing pervasive developmental disorders, such as autism, are described. Methods that have been used to treat autism and related developmental disorders were reviewed extensively and recently in the Comparative Effectiveness Review No. 26 of the Agency for Healthcare Research and Quality of the U.S. Department of Health and Human Services. That review also analyzes the efficacy of the treatment methods [WARREN Z, Veenstra-VanderWeele J, Stone W, et al. Therapies for Children With Autism Spectrum Disorders. Comparative Effectiveness Review No. 26. (Prepared by the Vanderbilt Evidence-based Practice Center under Contract No. 290-2007-10065-I.) AHRQ Publication No. 11-EHC029-EF. Rockville, Md.: Agency for Healthcare Research and Quality. April 2011, 908 pp]. In that publication, treatment methods are organized into four groups: Behavioral Interventions, Educational Interventions, Medical Interventions (including dietary methods), Allied Health Interventions (e.g., language, sensory, and auditory interventions), and Complementary and Alternative Medicine (CAM) Interventions.
Behavioral interventions were the first to show that it is in fact possible to treat autistic children. The interventions may take place at home, at school, and/or at a clinic and may involve a trained professional as well as the parents of the autistic child, often for several years of 40 hours per week of one-on-one sessions. Many such programs make use of applied behavior analysis in which there is (1) a request for the child to perform an action, (2) a response on the part of the child, and (3) a consequence which can range from strong positive reinforcement to strong negative reinforcement. As ordinarily practiced nowadays, only positive reinforcement is given (typically, verbal praise, a favored snack food, or time with a preferred toy). The design of the program includes selecting the behaviors or skills that are to be achieved. Thus, the child may be taught social, motor, and verbal behavior and cognitive skills, and can also be taught not to engage in undesirable behaviors. The program is preferably individualized to the needs of each child. Individual requests to the child are selected after having first dissected an overall behavior that is desired into component parts, and the training may consist of reinforcing the individual components, then reinforcing the chain of components so as to achieve the desired overall behavior.
An intervention program will also design the way that reinforcement is applied at different stages of conditioning the child (e.g., eventually eliminating reinforcement after the child has fully acquired the desired behavior). Skills may also be exercised in a more natural setting than the controlled home or clinical environment in which it was first taught. The UCLA/Lovaas-based interventions are perhaps the best known such interventions, but other behavioral intervention programs include special social skills interventions, play/interaction-based interventions, the Early Start Denver Model (ESDM), less intensive interventions focusing on providing parent training, cognitive behavioral therapy, neurofeedback, and sleep interventions. Whatever intervention method is used, it is advised to begin therapy at as early an age as practical, possibly age 2 or 3 [ROGERS S J, Vismara L A. Evidence-based comprehensive treatments for early autism. J Clin Child Adolesc Psychol 37(1, 2008):8-38; VISMARA L A, Rogers S J. Behavioral treatments in autism spectrum disorder: what do we know? Annu Rev Clin Psychol 6 (2010):447-468]
Educational interventions are also often based on applied behavior analysis and are sometimes intended for special-needs instruction in elementary schools. Ten such educational programs are reviewed in a publication of the National Research Council. Those programs are as follows: Children's Unit, Denver Community Based Approach, Developmental Intervention Model, Douglass, Individualized Support Program, LEAP, Pivotal response training, TEACCH, UCLA Young Autism Project, and Walden [Catherine LORD and James P. McGee, Eds., and National Research Council Committee on Educational Interventions for Children with Autism. Educating children with autism. Washington, D.C.: National Academy Press (2001)].
There are a few medical interventions for ASD, but no medications are currently available to treat its core symptoms. However, there is preliminary evidence that the diuretic bumetanide might be helpful [LEMONNIER E, Degrez C, Phelep M, Tyzio R, Josse F, Grandgeorge M, Hadjikhani N, Ben-Ari Y. A randomised controlled trial of bumetanide in the treatment of autism in children. Transl Psychiatry 2 (2012):e202, pp. 1-8]. Also, evidence favors the use of medications to address challenging behaviors of autistic children, using risperidone and aripiprazole (for tantrums, disruptive behavior, aggression towards others, self-injury, quickly changing moods, and irritability) [LESKOVEC T J, Rowles B M, Findling R L. Pharmacological treatment options for autism spectrum disorders in children and adolescents. Hary Rev Psychiatry 16(2, 2008):97-112; McPHEETERS M L, Warren Z, Sathe N, Bruzek J L, Krishnaswami S, Jerome R N, Veenstra-Vanderweele J. A systematic review of medical treatments for children with autism spectrum disorders. Pediatrics 127(5, 2011):e1312-e1321]. Drugs are also used to treat co-morbid conditions of autism, such as epilepsy.
A large number of dietary supplement, special diet, language, sensory, and auditory interventions, as well as complementary and alternative medicine interventions have been used to treat the symptoms of autism. According to ROSSIGNOL, melatonin, antioxidants, acetylcholinesterase inhibitors, naltrexone, and music therapy appear to show benefits. LEVY recommended the use of melatonin but found that there was insufficient evidence to recommend the use of other such therapies [ROSSIGNOL D A. Novel and emerging treatments for autism spectrum disorders: a systematic review. Ann Clin Psychiatry 21(4, 2009):213-236; LEVY S E, Hyman S L. Complementary and alternative medicine treatments for children with autism spectrum disorders. Child Adolesc Psychiatr Clin N Am 17(4, 2008):803-820].
When acupuncture is used to treat autistic individuals, the points of stimulation are LI4 on the hand where the thumb and first finger meet, PC6 on the palm-side of the forearm above the crease of the wrist, ST36 on the calf near the knee, and SP6 on the calf near the ankle. The putative mechanism of such acupuncture treatment is via changes in levels of arginine-vasopressin and oxytocin [ZHANG R, Jia M X, Zhang J S, Xu X J, Shou X J, Zhang X T, Li L, Li N, Han S P, Han J S. Transcutaneous electrical acupoint stimulation in children with autism and its impact on plasma levels of arginine-vasopressin and oxytocin: a prospective single-blinded controlled study. Res Dev Disabil 33(4, 2012):1136-1146]. Apparently, no acupuncture point in the vicinity of a vagus nerve is used.
Magnetic stimulation has been used in an attempt to treat, diagnose, or characterize potentially autistic individuals. However, those magnetic stimulation methods, transcranial magnetic stimulation and transcranial direct current stimulation, have been applied only to the brain of those individuals, and not to a peripheral nerve, as disclosed here [DEMIRTAS-Tatlidede A, Vahabzadeh-Hagh A M, Pascual-Leone A. Can noninvasive brain stimulation enhance cognition in neuropsychiatric disorders? Neuropharmacology 64 (2013):566-578; Xuejun KONG. Clinical significance of functional MRI guided transcranial magnetic stimulation for autism. N A J Med Sci. 2(2, 2009):64-66; OBERMAN L, Eldaief M, Fecteau S, Ifert-Miller F, Tormos J M, Pascual-Leone A. Abnormal modulation of corticospinal excitability in adults with Asperger's syndrome. Eur J Neurosci 36(6, 2012):2782-2788; SOKHADZE E, Baruth J, Tasman A, Mansoor M, Ramaswamy R, Sears L, Mathai G, El-Baz A, Casanova M F. Low-frequency repetitive transcranial magnetic stimulation (rTMS) affects event-related potential measures of novelty processing in autism. Appl Psychophysiol Biofeedback 35(2, 2010):147-161; SOKHADZE E M, El-Baz A, Baruth J, Mathai G, Sears L, Casanova M F. Effects of low frequency repetitive transcranial magnetic stimulation (rTMS) on gamma frequency oscillations and event-related potentials during processing of illusory figures in autism. J Autism Dev Disord 39(4, 2009):619-634; STAMOULIS C, Oberman L M, Praeg E, Bashir S, Pascual-Leone A. Single pulse TMS-induced modulations of resting brain neurodynamics encoded in EEG phase. Brain Topogr 24(2, 2011):105-113].
Invasive vagus nerve stimulation (VNS) is currently approved for the treatment of epilepsy in children older than 12 years, including children with autism spectrum disorders (also including Asperger syndrome children) and other pervasive developmental disorders such as Rett's syndrome. VNS may also be used investigationally in younger children as well, also including children with autism spectrum disorders [James W. WHELESS. Vagus nerve stimulation in pediatrics: determining appropriate candidates. Advanced Studies in Medicine 5(5B, 2005): S474-S476; BLOUNT J P, Tubbs R S, Kankirawatana P, Kiel S, Knowlton R, Grabb P A, Bebin M Vagus nerve stimulation in children less than 5 years old. Child's Nervous System 22(9, 2006):1167-1169]. Approximately 30% of epileptic children also have autism spectrum disorders, and approximately 30% of individuals with autism spectrum disorders have epilepsy [TUCHMAN R, Cuccaro M, Alessandri M. Autism and epilepsy: historical perspective. Brain Dev 32 (2010):709-718; TUCHMAN R, Rapin I. Epilepsy in autism. Lancet Neurol 1(6, 2002):352-358; BOLTON P F, Carcani-Rathwell I, Hutton J, Goode S, Howlin P, Rutter M. Epilepsy in autism: features and correlates. Br J Psychiatry 198(4, 2011):289-294]. Consequently, some data exist not only as to whether VNS is useful for the treatment of epilepsy in autistic children, but also whether the VNS affects the childrens' austic symptoms. However, the parameters of the electrical stimulation were chosen to treat the epilepsy, and not the autism, so the data concerning changes of autistic symptoms are essentially accounts of the side effects of the epilepsy treatment.
DANIELSSON et al. used invasive VNS to treat eight autistic children, four of which had also been diagnosed as having attention deficit hyperactivity disorder. They reported that two years of VNS treatment did not decrease the frequency of epileptic seizures in the children and had no positive cognitive effects. In one child, negative changes of general functioning were observed, but in three children, minor improvements in general functioning were measured through use of standard tests (Autistic Behavior Checklist; Autism Diagnostic Observation Schedule, Children's Global Assessment Scale, and Clinical Global Impressions-Improvement scale). The number of children was small, and there was no control group, so it is not clear from these data whether any changes in austistic symptoms were due to the VNS treatment, to other diverse treatments that the children were also receiving, or to the natural progression of autistic symptoms [DANIELSSON S, Viggedal G, Gillberg C, Olsson I. Lack of effects of vagus nerve stimulation on drug-resistant epilepsy in eight pediatric patients with autism spectrum disorders: a prospective 2-year follow-up study. Epilepsy Behav 12(2, 2008):298-304].
MURPHY et al. performed invasive VNS with six patients with medically refractory epilepsy secondary to hypothalamic hamartomas, four of which had severe autistic behaviors. Seizure control was found in three of the patients, and improved behavior was observed in all four of the autistic children [MURPHY J V, Wheless J W, Schmoll C M. Left vagal nerve stimulation in six patients with hypothalamic hamartomas. Pediatr Neurol 23(2, 2000):167-168]. In patent application US20050187590, entitled Method and system for providing therapy for autism by providing electrical pulses to the vagus nerve(s), to BOJEVA et al, the publication by MURPHY was noted, and it was further disclosed that an implanted vagus nerve stimulator could be used to treat autism. However, unlike the present disclosure, their application did not disclose any step that is unique to the treatment of autism or to a related neuro-developmental disorder.
LEVY et al examined a registry of patients with implanted VNS stimulators and found that after treatment, patients with autism have epileptic symptoms that are similar to those of patients without autism. Among quality of life indicators only the one, improved mood after 12 months of treatment, was found to be better in autistic patients as compared with non-autistic patients [LEVY M L, Levy K M, Hoff D, Amar A P, Park M S, Conklin J M, Baird L, Apuzzo M L. Vagus nerve stimulation therapy in patients with autism spectrum disorder and intractable epilepsy: results from the vagus nerve stimulation therapy patient outcome registry. J Neurosurg Pediatr 5(6, 2010):595-602].
PARK investigated 59 epileptic patients with autism, nineteen of whom had Lennox-Gastaut syndrome. He found that more than half of the patients had a reduction in seizure frequency after 12 months and that the quality of life generally improved in the patients, with some 76% of them experiencing an improved alertness [PARK Y D. The effects of vagus nerve stimulation therapy on patients with intractable seizures and either Landau-Kleffner syndrome or autism. Epilepsy Behav 4(3, 2003):286-290].
WARWICK et al described the case of one epileptic patient with Asperger syndrome. After six months of treatment using invasive VNS, the number of seizures and the duration of seizures were reduced. Furthermore, using modified Yale-Brown Obsessive Compulsive Scale and quality of life scales, after six months of VNS treatment, the patient was found to have improved Abnormal Nonverbal, Social Interaction, and Emotional Scores, as well as improved mood and memory [WARWICK T C, Griffith J, Reyes B, Legesse B, Evans M. Effects of vagus nerve stimulation in a patient with temporal lobe epilepsy and Asperger syndrome: case report and review of the literature. Epilepsy Behav 10(2, 2007):344-347].
WILFONG described the use of VNS treatment for epilepsy in seven Rett syndrome patients. The investigators found that after 12 months of treatment, there was a decrease in seizure frequency in six of them, that the patients were more alert, but there were not changes in mood or communication abilities [WILFONG A A, Schultz R J. Vagus nerve stimulation for treatment of epilepsy in Rett syndrome. Dev Med Child Neurol 48(8, 2006):683-686].
The publications that were cited above suggest that invasive vagus nerve stimulation may be useful in the treatment of autistic children who have epilepsy. WALKER et al performed animal experiments that addressed the issue of whether there are common neural pathways relating to seizures and autism-like behaviors, which may explain why epilepsy is found in approximately 30% of autistic children. They made lesions in rats that specifically target forebrain and cerebellar neurons, in order to create behaviors in rats that are similar to behavioral deficits seen in epilepsy and autism. They conclude that epilepsy and autism may have common neural pathways, and when that is the case, VNS might be used as a treatment for the autism [WALKER B R, Diefenbach K S, Parikh T N. Inhibition within the nucleus tractus solitarius (NTS) ameliorates environmental exploration deficits due to cerebellum lesions in an animal model for autism. Behav Brain Res 176(1, 2007):109-120].
However, there is no suggestion in these publications that vagus nerve stimulation could be used to treat autistic children who do not have epilepsy, and in fact, the parameters of the nerve stimulation (pulse width, frequency, etc.) were chosen to treat the epilepsy, without regard to the symptoms of autism. Furthermore, there is no suggestion that the vagus nerve stimulation could be applied noninvasively. Similarly, the use of deep brain stimulation to treat autism has only been mentioned in connection with the primary treatment of another disorder such as epilepsy or movement disorders [Anya McLAREN. Deep brain stimulation: a potential therapy for epilepsy and movement disturbances in autism spectrum disorders? Journal on Developmental Disabilities 13 (3, 2007): 167-186]. However, something similar to deep brain stimulation for the treatment of autism was disclosed in U.S. Pat. No. 7,623,927, entitled Modulation of the brain to affect psychiatric disorders, to REZAI, and in application US20090326605, entitled Treatment of language, behavior and social disorders, to MORRELL.
The psychology literature also refers to vagus nerve stimulation in young children who are at risk for developmental difficulties, but that stimulation consists of massage, kangaroo care, and similar tactile interventions, not electrical stimulation of the vagus nerve. The rationale for such tactile intervention is that the vagus nerve in the at-risk children has low tone, as evidenced primarily by unusually low respiratory sinus arrhythmia. The tactile stimulation is thought to increase the vagal tone, resulting in more normal attentiveness, facial expressions and vocalizations [FIELD T, Diego M. Vagal activity, early growth and emotional development. Infant Behav Dev 31(3, 2008):361-373].
PORGES and colleagues expand on that concept, arguing that developmental disorders are caused by, or are associated with, abnormalities in the autonomic nervous system generally, because the autonomic nervous system modulates affective experience, emotional expression, facial gestures, vocal communication and contingent social behavior. As an example, PORGES points to rocking and swinging of an autistic child, in which the position of the head is changed relative to the position of the heart. This will stimulate the baroreceptors and thereby engage autonomic heartrate/blood pressure feedback control loops. According to PORGES, this suggests that the frequently observed rocking and swinging behaviors in autistic individuals may reflect a naturally occurring biobehavioral strategy to stimulate and regulate a vagal system that is not efficiently functioning. However, despite his recognition of the potential of vagus nerve stimulation to help epileptic individuals with autistic-like behavior as described above in the publication by MURPHY, PORGES did not develop vagus nerve stimulation interventions to treat autonomic dysfunction in autistic children. Instead, he disclosed a behavioral intervention that uses acoustic stimulation to improve social behavior, and tested the approach with children diagnosed with autism. With that intervention, computer altered acoustic stimulation was presented in 45-min sessions, during which attempts were made to maintain the child in a calm behavioral state [PORGES S W. The polyvagal theory: phylogenetic substrates of a social nervous system. Int J Psychophysiol 42(2, 2001):123-46; PORGES S W. The Polyvagal Theory: phylogenetic contributions to social behavior. Physiol Behav 79(3, 2003):503-513; PORGES S W, Furman S A. The Early Development of the Autonomic Nervous System Provides a Neural Platform for Social Behavior: A Polyvagal Perspective. Infant Child Dev 20(1, 2011):106-118].
In the present disclosure, applicants teach the use of noninvasive vagus nerve stimulation (VNS) to treat autism spectrum disorders and other pervasive developmental disorders, irrespective of whether the patient also experiences epileptic seizures. One problem that may arise in performing the VNS noninvasively is that it requires the cooperation of the patient when applying the stimulator for an extended period of time to the patient's neck. For children with behavioral problems, the invention teaches that restraining the problematic child to apply the stimulator may not be necessary, provided that the child is initially taught or trained to actually want the stimulator to be applied. Thus, in one aspect of the invention, the child is initially stimulated noninvasively in such a way as to feel euphoric and therefore will not resist subsequent applications of the stimulator. Methods for creating a euphoric mental state using VNS were disclosed in a commonly assigned, co-pending application Ser. No. 13/024,727, entitled Non-invasive methods and devices for inducing euphoria in a patient and their therapeutic application, to SIMON et al, which is hereby incorporated by reference.
Having achieved the willingness of the child to undergo the noninvasive VNS through the induction of euphoria, the euphoric stimulation might then be provided only when the child performs a desirable task, thereby using the VNS as a conditioning stimulus for behavioral therapy. In another aspect of the invention, disclosed waveforms of the VNS are selected to inhibit or activate particular neural networks of the brain that are associated with autistic behavior and that become abnormal during the course of a child's development. That is to say, the invention is intended to provide a much-needed medical intervention. The methods may also be applicable to psychological developmental disorders generally. Such disorders include disorders of psychological development other than pervasive developmental disorders (i.e., ICD 10 classifications F80-F89 other than F84) and Intellectual Developmental Disorders (i.e. ICD 10 classifications F70-F79) which, like autism, have a strong genetic basis for causing developmental cognitive abnormalities (e.g., Down syndrome, Klinefelter's syndrome, Fragile X syndrome, neurofibromatosis, congenital hypothyroidism, Williams syndrome, phenylketonuria and Prader-Willi syndrome). The methods may also be applicable to some behavioral and emotional disorders with onset usually occurring in childhood and adolescence (ICD 10 classifications F90-F98), which are commonly comorbid with autism. This would include disturbances of activity and attention (attention deficit disorder, F90.0).